Compositions and Articles Comprising Complexes of 1-methylcycloproprene and Alpha-cyclodextrin

ABSTRACT

Compositions comprising complexes of 1-methylcyclopropene and α-cyclodextrin, and articles including the composition, are provided. Methods for using the compositions and articles in delaying the maturation of fruits, vegetables, and plants are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT/EP2019/060816, filed on Apr.26, 2019, which claims priority to Polish Patent Application No.P.425413, filed on 27 Apr. 2018, to Polish Patent Application No.P.425414, filed on 27 Apr. 2018, and to Polish Patent Application No.P.425415, filed on 27 Apr. 2018, all of which are incorporated byreference in their entireties.

TECHNICAL FIELD

This invention relates to compositions comprising complexes of1-methylcyclopropene and α-cyclodextrin, and articles (such as labels,sticks, and packaging) that include these complexes for use in delayingthe maturation of, e.g., fruits, vegetables, and plants.

BACKGROUND

Ethylene affects a wide range of physiological processes in plants,including fruits, vegetables, and flowers, such as drooping, aging andmaturation, chlorophyll loss, softening, physiological disorders,germination, isocoumarin synthesis, lignification, discoloration(browning), decomposition, and stimulation of defense systems. Whenstoring plant products, it is essential to control the influence ofethylene to prolong the durability of these products, delay theirmaturation, browning or aging.

One of the methods used is to inhibit the action of ethylene by blockingethylene receptors in plant cells. 1-methylcyclopropene (1-MCP) is a gasthat has been used for this purpose. 1-MCP, which may be provided in theform of a complex with α-cyclodextrin, is released upon exposure towater, e.g., in the form of humidity.

SUMMARY

In a first aspect, there is described a composition that includes: (a) acomplex of 1-methylcyclopropene and α-cyclodextrin and (b) a polymerbinder selected from the group consisting of polyvinylpyrollidone andcopolymers thereof, polyvinyl alcohol and copolymers thereof, polyvinylacetate copolymers, and combinations thereof. In some embodiments, theratio of polymer binder to complex on a weight to weight basis rangesfrom about 0.5:1 to about 3:1. In some embodiments, the ratio of polymerbinder to complex on a weight to weight basis ranges from about 0.5:1 toabout 4:1. The composition is capable of releasing the1-methylcyclopropene in the form of a gas when exposed to moisture andhas a release profile characterized in that when exposed at roomtemperature in a sealed vessel to conditions of 85% relative humidity,the composition releases substantially no 1-methylcyclopropene after atime period of at least 1 hour after exposure and thereaftercontinuously releases 1-methylcyclopropene for at least 5 hours afterexposure.

In some embodiments, the ratio of polymer binder to complex on a weightto weight basis is about 1:1. In some embodiments, the polymer binderhas a molecular weight ranging from about 5,000 to about 15,000 (e.g.,about 10,000). In some embodiments, the 1-methylcyclopropene is presentin the composition in an amount of from about 0.825 wt % to about 2.2 wt%. In some embodiments, the 1-methylcyclopropene is present in thecomposition in an amount of from about 0.66 wt % to about 2.2 wt %.

In some embodiments, the composition includes a hygroscopic agent, e.g.,a hygroscopic agent selected from the group consisting of glycerol,glucose, and combinations thereof. In some embodiments, the compositionincludes a humidity-indicating dye. Examples of suitablehumidity-indicating dyes include quinolone yellow, curcumin (alone or incombination with sodium hydrogen carbonate, tetrabutylammonium hydroxide(TBAOH), or patent blue), patent blue, hydrochromic ink, thymol blue(alone or in combination with TBAOH), bromothymol blue (alone or incombination with TBAOH or bromochlorophenol blue), indigo carmine (aloneor in combination with TBAOH), bromochlorophenol blue (alone or incombination with TBAOH or acetic acid), and Reichardt's dye (alone or incombination with TBAOH).

In some embodiments, the composition has a release profile characterizedin that when exposed at room temperature in a sealed vessel toconditions of 85% relative humidity, the composition releasessubstantially no 1-methylcyclopropene after 2 hours or after 3 hours. Insome embodiments, the composition has a release profile characterized inthat when exposed at room temperature in a sealed vessel to conditionsof 85% relative humidity, the composition releases substantially no1-methylcyclopropene after a time period of at least 1 hour or at least3 hours after exposure and thereafter continuously releases1-methylcyclopropene for at least 24 hours after exposure. Preferably,the compositions do not release 1-methylcyclopropene when the relativehumidity at room temperature is less than 60%.

The composition may be in the form of a stick that can be manuallyapplied to a surface of a substrate. Alternatively, the composition maybe included in an adhesive label where the label includes a substratehaving a first surface and a second surface in which the composition isprovided on the first surface and an adhesive provided on the secondsurface. Example of suitable substrates include paper, cardboard, andsynthetic substrates.

Where the composition is designed for use in a label, the compositionmay be prepared from a precursor composition that includes the complex,polymer binder, and a solvent, e.g., propanol, especially 2-propanol.Preferably, the polymer, solvent, and 1-methylcyclopropene complex withα-cyclodextrin are combined in a ratio of 1:2:1, 2:2:1, 1:2:1.Preferably, the precursor composition contains 20-45% polymer, 40-55%solvent and 15-40% complex of 1-methylcyclopropene withalpha-cyclodextrin. Preferably, the precursor composition comprisesglycerol, e.g, 5-20% glycerol. The precursor composition may alsoinclude plasticizers and/or compounds that increase the humidity of theactive layer.

In some embodiments, the labels are prepared by a) preparing a pastefrom the composition ingredients as defined above, b) applying a screenlayer of paste to the substrate (e.g., adhesive paper layer) with ascreen printing technique, and c) drying the resulting layer structureto remove solvent. In some embodiments, the thickness of the1-MCP-containing layer in the label can vary depending on the screenprint mesh used. As the mesh size number increases, less compositioncontaining 1-MCP is applied. Thus, thickness of the 1-MCP-containinglayer in the label can decrease with increasing mesh size number. A widerange of mesh sizes can be used to produce varying thicknesses of the1-MCP-containing layer in the label. Preferably, screen print mesh sizes32T, 43T, 47T, 48T, 64T, and 68T are used.

The labels may be used in a method for prolonging plant life anddelaying the ripening process of fruit and vegetables comprising placinga label as defined above inside a package for storing plant products andexposing it on humidity conditions produced in the package by plantproducts.

The label, due to its composition and construction, releases 1-MCP gasunder the influence of moisture generated in the natural process offruit and vegetable breathing. Under normal conditions of humidity,e.g., up to 60% or 75% relative humidity, the label is stable. Abovethis level, there is a gradual release of 1-MCP gas from the surface ofthe label after a period of time. The polymer binder (e.g., the PVPpolymer) acts as a binding agent and at the same time absorbs ambientmoisture. One advantage of this type of binder for 1-MCP is the ease ofits use, versatility, the flexibility of the form, and the possibilityof straightforward modification to the customer's needs.

The layered design of the label sticker can be modified over anextensive range. Depending on the time required for the release of 1-MCPand relative humidity, the label can be covered with additionalfunctional layers (barrier polymers, hydrophilic, hydrophobic,hygroscopic additives, etc.). The size of the label can also vary basedon the size of the package and the weight of fruit/vegetables in thispackage, and the necessary concentration of 1-MCP to be achieved.

Preferably, to assist the end user, the label includes an indicator tocommunicate to the end user that 1-MCP has been released and has reachedan effective concentration. This can be achieved by adding a moistureindicator function to the label in the form of an appearing figure or acolored bar. The attainment of at least 85% humidity, which is indicatedon the label, is synonymous with the release of 1-MCP.

The compositions have a viscosity, density, and cohesion that enablethem to be applied to substrate surfaces, e.g., by screen printing toobtain an active layer of appropriate and reproducible thickness. Theyprolong the durability of fruits, vegetables, ornamental plants, etc.,because they release gaseous 1-methylcyclopropene after reaching theappropriate level of ambient relative humidity at a given temperature(such as 85% at room temperature) or absolute humidity denoting thewater content in g/m³.

As noted above, the composition may be provided in the form of a stickfor application to a surface (e.g., by spreading manually). To form thestick, the 1-methylcyclopropene/α-cyclodextrin complex is combined witha multicomponent mixture comprising polymers, waxes, paraffin, mono- andpolyhydric alcohols, dyes, and/or excipients that are molded into astick. The stick forms a soft substance in the shape of an a rod that,in turn, is embedded in a case that allows pulling out, forself-application outside or inside packages for storing fruit,vegetables or flowers (FIG. 34).

In some embodiments, the stick includes a molded mass contains 5-50 wt.% 1-methylcyclopropene/α-cyclodextrin complex, 2-45 wt. % polymer binder(e.g., polyvinylpyrrolidone (PVP)), and a casing in which the column isembedded. The mass may further include polymers, waxes, paraffin, mono-and polyhydric alcohols, dyes (e.g., cochineal red), and auxiliarycomponents. Specific examples include coconut oil, SE-PF emulsifier,beeswax, stearic acid, candelilla wax, glycerol, and isopropyl alcohol.In some embodiments, the mass includes components selected from 0.5 wt.% dyes, 49.5 wt. % isopropyl alcohol, 53 wt. % coconut oil, 20 wt. %SE-PF emulsifier, 7.5-24 wt. % beeswax, 10 wt. % stearic acid, 7.5-24wt. % candelilla wax, and/or 15-30 wt. % glycerin.

In one embodiment, the components of the mass constitute 45 wt. %polyvinylpyrrolidone (PVP), 5 wt. % 1-methylcyclopropene/α-cyclodextrincomplex, 0.5 wt. % cochineal red, and 49.5 wt. % isopropyl alcohol.

In one embodiment, the components of the mass constitute 53 wt. %coconut oil, 20 wt. % SE-PF emulsifier, 10 wt. % stearic acid, 9.5 wt. %beeswax, 0.5 wt. % cochineal red, 2 wt. % polyvinylpyrrolidone (PVP),and 5 wt. % 1-methylcyclopropene/α-cyclodextrin complex.

In one embodiment, the components of the mass constitute 50 wt. %1-methylcyclopropene/α-cyclodextrin complex, 24 wt. % beeswax, 24 wt. %candelilla wax, and 2 wt. % polyvinylpyrrolidone (PVP).

In one embodiment, the components of the mass constitute 30 wt. %1-methylcyclopropene/α-cyclodextrin complex, 20 wt. % beeswax, 20 wt. %candelilla wax, and 30 wt. % polyvinylpyrrolidone (PVP).

In one embodiment, the components of the mass constitute 20 wt. %beeswax, 20 wt. % candelilla wax, 30 wt. %1-methyl-cyclopropene/α-cyclodextrin complex, and 30 wt. %polyvinylpyrrolidone (PVP).

In one embodiment, the components of the mass constitute 35 wt. %1-methylcyclopropene/α-cyclodextrin complex, 30 wt. % glycerol, and 35wt. % polyvinylpyrrolidone (PVP).

In one embodiment, the components of the mass constitute 7.5 wt. %beeswax, 7.5 wt. % candelilla wax, 15 wt. % glycerol, 30 wt. %1-methylcyclopropene/α-cyclodextrin complex, and 30% wt.polyvinylpyrrolidone (PVP).

The stick may be used to apply the composition to packaging in the formof paper, cardboard, or foil.

Use of the stick inhibits the process induced by ethylene, thus delayingthe maturation and aging of plant products, by spreading the stick massdefined above on a material for packaging, storing a plant product fromthe inside of the package in which the plant product is found, andclosing the packaging. 1-MCP release occurs after at least one hour whenthe relative humidity within the packaging reaches about 85%.

In a second aspect, there is described a composite mixture comprising acomplex of 1-methylcyclopropene with α-cyclodextrin and copolymers ofethylene and vinyl acetate characterized by a melting point of 47-100°C., mixed in a weight ratio of 1:3. Examples of ethylene vinyl acetatecopolymers are ethylene vinyl acetate copolymers have a vinyl acetatecontent of 17% to 41%, ethylene and vinyl acetate modified maleicanhydride, ethylene vinyl acetate copolymer modified with acrylic acid,and ethylene vinyl acetate copolymer with acetate content from 7.5% to40%.

Also described is a granulate for an active layer of a PET compositefilm comprising the composite mixture described above.

Also described is a PET polyester composite film comprising in theactive layer a granulate as described above. In some embodiments, thegranulate content in the active layer is 0.1-5 wt %, e.g., 1 wt %.

In some embodiments, the PET film includes at least two active layersand at least one support layer, and is present in the ABA format where Ais the active layer containing the 1-MCP/α-cyclodextrin complex and B isthe carrier layer containing polyethylene. The active layer may beplaced between the support layers.

In some embodiments, the active layer is 10% to 30% of the thickness ofthe composite film, and the support layer is 70-90%. The total thicknessof the film may be 0.1-2 mm.

Also described is a process for preparing a PET composite filmcomprising a 1-methylcyclopropene complex with α-cyclodextrin thatincludes: (a) mixing the 1-methylcyclopropene/α-cyclodextrin complexwith a copolymer of ethylene and vinyl acetate; (b) extruding themixture obtained in step (a) to form a composite; (c) cooling andmechanically granuate the composite to form granules; (d) mixing thegranules obtained in step (c) with carrier polymer granules to form agranule mixture; and e) co-extruding the granule mixture obtained instep (d) at 230° C. to 275° C., preferably 230 to 260° C., to form thecomposite film.

In some embodiments, the 1-methylcyclopropene/α-cyclodextrin complex ismixed with a 1:3 copolymer of ethylene and vinyl acetate in a weightratio of 1:3. Examples of suitable ethylene vinyl acetate copolymers aredescribed above.

In some embodiments, the extrusion in step (b) is carried out at 80° C.

In some embodiments, the granulate obtained in step (c) is mixed withthe carrier polymer granules in step (d) in a weight ratio of A:B from1:9 to 1:2.33.

In some embodiments, in step (e), a composite film is co-extruded in athree-layer system ABA, where layer A forms an upper layer in contactwith layer B, and layer A forms a bottom layer in contact with layer B,wherein layer A is a layer obtained from the granulate obtained in step(c), and the layer B is a carrier polymer.

In some embodiments, the co-extrusion process is carried out with asingle-screw or twin-screw extruder.

The PET polyester composite film may be used to manufacture of fruit andvegetable storage packaging, e.g., thermoformable packaging.

The mixture of 1-methylcyclopropene/α-cyclodextrin complex with polymersthat are characterized by a high melt flow index and compatibility withpolyester polymers (e.g, polyethylene terephthalate) makes it possibleto incorporate the granulate as an additive to the outer layer in anextrusion process of PET film in ABA format, where A is a layercomprising a 1-MCP/α-cyclodextrin complex, hereinafter referred to as anactive layer (FIG. 39). The granulate is obtained by melting and mixingthe ingredients, followed by extrusion, cooling, and granulation.

In some embodiments, films have been prepared in which 1-MCP modifiedpolyethylene is used as the active layer and placed between polyethylenelayers or as a binder of two polyethylene films, where the polyethylenefilms are derivatives of high melt flow and lowmelting/softening/molding polyethylene. Specifically, a granulatecomprising a 1-MCP/α-cyclodextrin complex and an ethylene vinyl acetatecopolymer (for example Evatane (Arkema), Elvax (Dupont), Bynel (Dupont)having a melting point in the range of 47-100° C. have been prepared.The granules prepared in this way are used as a 1% addition to the outerlayer of PET film extruded in the ABA system at a temperature of230-260° C. and even up to 275° C. The co-extrusion process is carriedout using an extruder. The addition of the granulate is in the range of0.1-5% by weight in the outer layer, which is from 10% to 30% of thethickness of the extruded film. The thickness of the film is 0.1-2 mm.

The resulting PET co-extruded films release 1-MCP under the influence ofmoisture. Due to the natural hygroscopicity of PET, it is not necessaryto include an additive that causes water absorption. It is also possibleto obtain a PET film containing 1-MCP in a one-stage extrusion process,rather than a multistage lamination process, which is much moretechnologically complicated. Furthermore, the method allows theproduction of films of different thickness, as well as 1-MCP contentonly in the outer layer. The method also allows the production ofpackages by thermoforming from the obtained film (e.g., shell-typecloths) for storing fruit, vegetables, and flowers. Active 1-MCP isreleased under the influence of moisture generated in the naturalbreathing process of fruits and vegetables after they have been placedin a container.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1. is an exploded perspective view of a functional sticker with anactive layer containing 1-MCP.

FIG. 2 is a graph showing dependence of the concentration of isolated1-MCP (mL/L) from a time (h) at a relative humidity of 85% and 100% forExample A-1.

FIG. 3 is a graph showing dependence of the concentration of isolated1-MCP (mL/L) from a time (h) in the moisture content of apple forExample A-1.

FIG. 4 is a graph showing dependence of the concentration of isolated1-MCP (μL/L) from a time (h) at a relative humidity of 100% at 6° C. forExample A-1.

FIG. 5 is a graph showing dependence of the released 1-MCP concentration(mL/L) from time (h) at 85% and 100% relative humidity for Example A-2.

FIG. 6 is a graph showing dependence of the concentration of isolated1-MCP (μL/L) from a time (h) at a relative humidity of 100% at 6° C. forExample A-2.

FIG. 7 is a graph showing dependence of the concentration of isolated1-MCP (mL/L) from a time (h) at a relative humidity of 85% and 100% forExample 3.

FIG. 8 is a graph showing dependence of the concentration of isolated1-MCP (μL/L) from a time (h) at a relative humidity of 100% at 6° C. forExample A-3.

FIG. 9 is a graph showing dependence of the concentration of isolated1-MCP (mL/L) from a time (h) at a relative humidity of 85% and 100% forExample A-4.

FIG. 10 is a graph showing dependence of the concentration of isolated1-MCP (μL/L) from a time (h) at a relative humidity of 100% at 6° C. forExample A-4.

FIG. 11 is a graph showing dependence of the concentration of isolated1-MCP (mL/L) from a time (h) at a relative humidity of 85% and 100% forExample A-5.

FIG. 12A is a chromatogram from which the concentration presented inFIG. 11 was determined.

FIG. 12B is a chromatogram from which the concentration presented inFIG. 11 was determined.

FIG. 13A is a chromatogram from which the concentration presented inFIG. 11 was determined.

FIG. 13B is a chromatogram from which the concentration presented inFIG. 11 was determined.

FIG. 14 is a graph showing dependence of 1-MCP isolated concentration(mL/L) from time (h) at 75% and 80% relative humidity for Example A-6.

FIG. 15 is a graph showing dependence of the secreted concentration of1-MCP (mL/L) from a time (h) at a relative humidity of 85% and 100% forExample A-7.

FIG. 16 is a graph showing concentration of 1-MCP released over time percm² of Sample 1 of Example A-8 at 85% relative humidity.

FIG. 17 is a graph showing concentration of 1-MCP released over time percm² of Sample 2 of Example A-8 at 85% relative humidity.

FIG. 18 is a graph showing concentration of 1-MCP released over time percm² of Sample 3 of Example A-8 at 85% relative humidity.

FIG. 19 is a graph showing concentration of 1-MCP released over time percm² of Sample 4 of Example A-8 at 85% relative humidity.

FIG. 20 is a graph showing concentration of 1-MCP released over time percm² of Sample 5 of Example A-8 at 85% relative humidity.

FIG. 21 is a graph showing concentration of 1-MCP released over time percm² of Sample 6 of Example A-8 at 85% relative humidity.

FIG. 22 is a graph showing concentration of 1-MCP released over time percm² of Sample 7 of Example A-8 at 85% relative humidity.

FIG. 23 is a graph showing concentration of 1-MCP released over time percm² of Sample 8 of Example A-8 at 85% relative humidity.

FIG. 24 is a graph showing concentration of 1-MCP released over time percm² for a 5 cm² sample of Example A-8 at 85% relative humidity.

FIG. 25 is a graph showing concentration of 1-MCP released over time percm² for a 10 cm² sample of Example A-8 at 85% relative humidity.

FIG. 26 is a graph showing concentration of 1-MCP released over time percm² for a 20 cm² sample of Example A-8 at 85% relative humidity.

FIG. 27 is a graph showing concentration of 1-MCP released over time percm² for a 40 cm² sample of Example A-8 at 85% relative humidity.

FIG. 28 is a graph showing concentration of 1-MCP released over time percm² for Sample A, a 100 cm² sample, of Example A-8 at 85% relativehumidity.

FIG. 29 is a graph showing concentration of 1-MCP released over time percm² for Sample B, a 100 cm² sample, of Example A-8 at 85% relativehumidity.

FIG. 30 is a graph showing concentration of 1-MCP released over time percm² of Sample 1 of Example A-9 at 85% relative humidity.

FIG. 31 is a graph showing concentration of 1-MCP released over time percm² of Sample 2 of Example A-9 at 85% relative humidity.

FIG. 32 is a graph showing concentration of 1-MCP released over time percm² of Sample 1 of Example A-10 at 85% relative humidity.

FIG. 33 is a graph showing concentration of 1-MCP released over time percm² of Sample 2 of Example A-10 at 85% relative humidity.

FIG. 34 illustrates an example of a stick containing 1-MCP included in adispenser for applying the contents of the stick.

FIG. 35 is a chromatogram presented for the stick described in ExampleB-1. The 1-MCP retention time was 5.920 min. versus a retention time of6.395 min. for the cis-2-butene reference standard.

FIG. 36 is a chromatogram presented for the stick described in ExampleB-2. The 1-MCP retention time was 6.067 min. versus a retention time of6.540 min. for the cis-2-butene reference standard.

FIG. 37 is a graph showing the concentration of 1-MCP released over thetime from the stick described in Example B-3.

FIG. 38 is a graph showing the concentration of 1-MCP released over timefrom the stick described in Example B-4.

FIG. 39 shows the construction of a functional film in ABA format, whereABA means the system: active layer A/carrier layer B/active layer A.

FIG. 40 shows the chromatogram of air from a film sample made by headtechnique space.

FIG. 41 shows the mass spectrum of 1-methylcyclopropene.

FIG. 42 shows the mass spectrum of cis-2-butene.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The invention will now be described further by way of the followingexamples.

A. Labels

Example 1

Poly(vinylpyrrolidone) (MW=10,000) (25% by weight) was dissolved in2-propanol (50% by weight) and the1-methylcyclopropene/alpha-cyclodextrin complex (25% by weight) wasadded (the 1-MCP content in the complex was 3.3%). The resulting pastewas applied to self-adhesive paper by screen printing (polyester mesh64T, resolution 160 dpi). After drying at room temperature, labels werecut from the paper and tested by placing each in gas-tight containerswith sampling valves under conditions of defined humidity.

6.4 cm×4.6 cm labels were placed in a 900 ml glass vessel. A containerwith a saturated solution of the appropriate salt was placed in thevessel to obtain the correct relative humidity, or a sponge soaked inwater was placed in the vessel instead of salt solution to obtain 100%relative humidity. 250 μL of cis-2-butene was introduced into the vesselwith a gas-tight syringe.

The concentration of 1-MCP was determined as compared to cis-2-butene asa reference, using a gas chromatograph equipped with a PoraBOND Qcolumn: 25 m×0.25 mm internal diameter (i.d.)×3 μm and a flameionization detector (FID). Cis-2-butene was used as a reference becauseit has the same response from an FID detector as 1-methylcyclopropene.

For analysis, 250 μL gas was collected with a gas-tight syringe andinjected into the above-mentioned column under the following conditions:temperature of the split/splitless injector 120° C.; isothermal 120° C.,temperature of the FID 240° C. detector, split 20:1, carrier gas flow(helium) 50 cm/s.

Example 2

Poly(vinylpyrrolidone) (MW=10,000) (40 wt %) was dissolved in 2-propanol(40 wt %) and the 1-methylcyclopropene/alpha-cyclodextrin complex (20 wt%) was added (the 1-MCP content in the complex was 3.3%). The resultingpaste was applied to the self-adhesive paper by screen printing(polyester mesh 64T, resolution 160 dpi). After drying at roomtemperature, labels were cut from the paper and tested by placing themin gas-tight containers with sampling valves under conditions of definedhumidity.

The concentration of 1-MCP was determined analogously to Example 1.

Example 3

Poly(vinylpyrrolidone) (MW=10,000) (20 wt %) was dissolved in 2-propanol(40 wt %) and the 1-methylcyclopropene/alpha-cyclodextrin complex (40 wt%) was added (the 1-MCP content in the complex was 3.3%). The resultingpaste was applied to the self-adhesive paper by screen printing(polyester mesh 64T, resolution 160 dpi). After drying at roomtemperature, labels were cut from the paper and tested by placing themin gas-tight containers with sampling valves under conditions of definedhumidity.

The concentration of 1-MCP was determined analogously to Example 1.

Example 4

Poly(vinylpyrrolidone) (MW=10,000) (45 wt %) was dissolved in 2-propanol(40 wt %) and the 1-methylcyclopropene/alpha-cyclodextrin complex (15 wt%) was added (the 1-MCP content in the complex was 3.3%). The resultingpaste was applied to the self-adhesive paper by screen printing(polyester mesh 64T, resolution 160 dpi). After drying at roomtemperature, labels were cut from the paper and tested by placing themin gas-tight containers with sampling valves under conditions of definedhumidity.

The concentration of 1-MCP was determined analogously to Example 1.

Example 5

Poly (1-vinylpyrrolidone-co-vinyl acetate) (MW=13,000) (25% by weight)was dissolved in 2-propanol (50% by weight) and the1-methylcyclopropene/alpha-cyclodextrin complex (25% by weight) wasadded (content 1-MCP in the complex was 3.3%). The resulting paste wasapplied to the self-adhesive paper by screen printing (polyester mesh64T, resolution 160 dpi). After drying at room temperature, labels werecut from the paper and tested by placing them in gas-tight containerswith sampling valves under conditions of defined humidity.

The concentration of 1-MCP was determined analogously to Example 1.

Example 6

Poly(vinylpyrrolidone) (MW=10,000) (20 wt %) was dissolved in 2-propanol(40 wt %) and the 1-methylcyclopropene/alpha-cyclodextrin complex (20 wt%) was added (the 1-MCP content in the complex was 3.3%), and glycerine(20% by weight). The resulting paste was applied to the self-adhesivepaper by screen printing (polyester mesh 64T, resolution 160 dpi). Afterdrying at room temperature, labels were cut from the paper and tested byplacing them in gas-tight containers with sampling valves underconditions of defined humidity.

The concentration of 1-MCP was determined analogously to Example 1.

Example 7

Poly(vinylpyrrolidone) (MW=10,000) (20 wt %) was dissolved in 2-propanol(55 wt %) and the 1-methylcyclopropene/alpha-cyclodextrin complex (20 wt%) was added (the 1-MCP content in the complex was 3.3%), and glycerine(5% by weight). The resulting paste was applied to the self-adhesivepaper using screen printing (polyester mesh 64T, resolution 160 dpi).After drying at room temperature, labels were cut from the paper andtested by placing them in gas-tight containers with sampling valvesunder conditions of defined humidity.

The concentration of 1-MCP was determined analogously to Example 1.

Example 8

A dry mixture of poly(vinylpyrrolidone) (MW=10,000) (50 wt %) and1-methylcyclopropene/alpha-cyclodextrin complex (50 wt %) was prepared.The dry mixture was combined with 2-propanol in an amount sufficient toform a paste (for every 10 g of dry mixture, between 5 mL and 20 mL2-propanol is used). The resulting paste was applied to self-adhesivepaper by screen printing (polyester mesh 64T, resolution 160 dpi). Afterdrying at room temperature, 6.4 cm×4.6 cm labels (29.44 cm²) were cutfrom the paper and tested for total amount of 1-MCP released and amountof 1-MCP released per cm² of the label, under 100% relative humidityconditions or 85% relative humidity conditions.

To test the samples under 100% relative humidity conditions, the sampleswere each placed in a 250 mL bottle and then 2 mL of distilled water wasadded. Next, the bottle was tightly closed and 250 μL of cis-2-butenewas added. To determine the total amount of 1-MCP released and theamount of 1-MCP released per cm² of label, the samples were analyzed ona gas chromatograph analogously to Example 1. Results are shown in Table1.

TABLE 1 Total 1-MCP released under 100% relative humidity Sample ASample B Sample C Sample D 1-MCP (mg/cm²) 0.04255 0.04784 0.051250.05601 1-MCP (μL) 17.6 19.8 21.2 23.2

To test the samples under 85% relative humidity conditions, the sampleswere each pasted in 900 mL vessels. To obtain a relative humidity of85%, a container with a saturated solution of potassium chloride wasplaced into the vessel. At 20° C., relative humidity for potassiumchloride is 85.11±0.29. The vessel was then tightly closed and 250 μL ofcis-2-butene was added. The samples were analyzed on a gas chromatographto measure the concentration of released 1-MCP from the sample overtime. At each time interval, samples were removed from the vessels andthe concentration was obtained by comparing the areas of the peaks(1-MCP and cis-2-butene). The results are shown in Tables 2-4 and FIGS.16-23.

TABLE 2 1-MCP released over time per cm² of label (μL/L) at 85% relativehumidity Time (h) Sample 1 Sample 2 1 — — 2 — — 3 1.18 0.46 4 2.10 1.515 2.79 2.35 6 2.91 2.72 7 3.35 3.18 9.5 4.17 3.84 26 5.81 5.28

TABLE 3.1 MCP released over time per cm² of label (μL/L) at 85% relativehumidity Time (h) Sample 3 Sample 4 1.5 — — 2.5 1.03 1.03 3.5 1.68 1.475.5 2.83 3.04 17.5 5.25 5.77 19 5.23 6.22 20.5 5.25 6.24

TABLE 4 1-MCP released over time per cm² of label (μL/L) at 85% relativehumidity Time [h] Sample 5 Sample 6 Sample 7 Sample 8 1 — — — — 3 0.740.78 1.11 0.67 4 1.18 1.2 1.53 1.02 6 1.71 1.78 1.71 1.66 20 2.41 2.822.63 2.84 21 2.48 2.65 2.56 2.53 25 2.74 3.09 2.47 2.8 27 3.22 3.47 3.23.23 68 3.22 3.94 2.94 3.47

The release profiles of different label sizes were also analyzed. Labelswere prepared as above, cut to size, and pasted into 2000 mL vessels. Toobtain a relative humidity of 85%, a container with a saturated solutionof potassium chloride was placed into the vessel. The vessel was thentightly closed and 250 μL of cis-2-butene was added. The samples wereanalyzed on a gas chromatograph to measure the concentration of released1-MCP from the sample over time as described above for 100% relativehumidity. The measurements are shown in Tables 5-6 and illustrated inFIGS. 24-29.

TABLE 5 1-MCP released over time under 85% relative humidity for varyinglabel sizes (μL/L) Time 5 cm² 10 cm² 20 cm² 40 cm² 0.5 — — — — 1 — — — —1.5 — — — — 2 — — — — 2.5 — — — 0.09 3 — 0.15 0.21 0.25 3.5 — — 0.5 0.36 4 0.75 0.71 0.75 0.47 4.5 — 0.93 0.91 0.69 5 1.19 1.19 — 0.91 5.51.69 1.33 0.97 1.03 6 2.04 — 1.11 1.27 24 2.49 2.72 2.59 2.58

TABLE 6 1-MCP released over time under 85% relative humidity 100 cm²labels (μL/L) Time 100 cm2 100 cm2 (h) (Sample A) (Sample B) 0.5 — — 1 —— 1.5 — — 2 — — 2.5 — — 3 — — 3.5 0.07 0.04 4 0.12 0.11 5 0.28 0.22 60.52 0.38 7 0.74 0.59 24 2.35 2.08 27.5 2.21 2.18

Example 9

A dry mixture of poly(vinylpyrrolidone) (MW=10,000) (50 wt %),1-methylcyclopropene/alpha-cyclodextrin complex (25 wt %), and purealpha-cyclodextrin (25 wt %) was prepared. The dry mixture was combinedwith 2-propanol in an amount sufficient to form a paste as described inExample A-8. The resulting paste was applied to self-adhesive paper byscreen printing (polyester mesh 64T, resolution 160 dpi). After dryingat room temperature, labels were cut from the paper and tested for totalamount of 1-MCP released and amount of 1-MCP released per cm² of thelabel, under 100% relative humidity conditions or 85% relative humidityconditions.

To test under 100% relative humidity conditions, a 6.4 cm×4.6 cm label(29.44 cm²) sample was placed in a 250 mL bottle and then 2 mL ofdistilled water was added. Next, the bottle was tightly closed and 250μL of cis-2-butene was added. To determine the total amount of 1-MCPreleased and the amount of 1-MCP released per cm² of label, the samplewas analyzed on a gas chromatograph as described in Example A-8. Thesample released 0.02364 mg/cm2 (or 9.8 μL) 1-MCP.

Two sample labels with a surface area of 20 cm² were tested under 85%relative humidity conditions as described in Example A-8. The resultsare shown in Table 7 and FIGS. 30-31.

TABLE 7 1-MCP released over time per cm² of label (μL/L) at 85% relativehumidity Time (h) Sample 1 Sample 2 1 — — 2 — — 3.5 0.399 0.381 5 —0.928 6 0.936 1.239 20.5 1.285 1.753 23 1.574 1.861 25 1.462 1.924

Example 10

A dry mixture of poly(vinylpyrrolidone) (MW=10,000) (66.7 wt %), and1-methylcyclopropene/alpha-cyclodextrin complex (33 wt %) was prepared.The dry mixture was combined with 2-propanol in an amount sufficient toform a paste as described in Example A-8. The resulting paste wasapplied to self-adhesive paper by screen printing (polyester mesh 64T,resolution 160 dpi). After drying at room temperature, labels were cutfrom the paper and tested for total amount of 1-MCP released and amountof 1-MCP released per cm² of the label, under 100% relative humidityconditions or 85% relative humidity conditions.

To test under 100% relative humidity conditions, a 6.4 cm×4.6 cm label(29.44 cm2) sample was placed in a 250 mL bottle and then 2 mL ofdistilled water was added. Next, the bottle was tightly closed and 250μL of cis-2-butene was added. To determine the total amount of 1-MCPreleased and the amount of 1-MCP released per cm2 of label, the samplewas analyzed on a gas chromatograph as described in Example A-8. Thesample released 0.02264 mg/cm′ (or 9.4 μL) 1-MCP.

Two sample labels with a surface area of 20 cm2 were tested under 85%relative humidity conditions as described in Example A-8. The resultsare shown in Table 8 and FIGS. 32-33.

TABLE 8 1-MCP released over time per cm² of label (μL/L) at 85% relativehumidity Time (h) Sample 1 Sample 2 1 — — 2 — — 3.5 0.416 0.529 5 1.2160.937 6 1.223 1.234 20.5 1.657 1.532 23 1.53  1.561 25 1.604 1.497

Example 11

A dry mixture of poly(vinylpyrrolidone) (MW=10,000) (50 wt %),1-methylcyclopropene/alpha-cyclodextrin complex (25 wt %), and glucose(25 wt %) was prepared. The dry mixture was combined with 2-propanol inan amount sufficient to form a paste as described in Example A-8. Theresulting paste was applied to self-adhesive paper by screen printing(polyester mesh 64T, resolution 160 dpi).

Example 12

A dry mixture of poly(vinylpyrrolidone) (MW=10,000) (50 wt %),1-methylcyclopropene/alpha-cyclodextrin complex (12.5 wt %), and purealpha-cyclodextrin (37.5 wt %) was prepared. The dry mixture wascombined with 2-propanol in an amount sufficient to form a paste asdescribed in Example A-8. The resulting paste was applied toself-adhesive paper by screen printing (polyester mesh 64T, resolution160 dpi).

Example 13

A dry mixture of poly(vinylpyrrolidone) (MW=10,000) (50 wt %),1-methylcyclopropene/alpha-cyclodextrin complex (12.5 wt %), and glucose(37.5 wt %) was prepared. The dry mixture was combined with 2-propanolin an amount sufficient to form a paste as described in Example A-8. Theresulting paste was applied to self-adhesive paper by screen printing(polyester mesh 64T, resolution 160 dpi).

Example 14

A dry mixture of poly(vinylpyrrolidone) (MW=10,000) (50 wt %),1-methylcyclopropene/alpha-cyclodextrin complex (25 wt %), purealpha-cyclodextrin (12.5 wt %), and glucose (12.5 wt %) was prepared.The dry mixture was combined with 2-propanol in an amount sufficient toform a paste as described in Example A-8. The resulting paste wasapplied to self-adhesive paper by screen printing (polyester mesh 64T,resolution 160 dpi).

B. Stick

Example 1

Polyvinylpyrrolidone (PVP) (45 wt. %, MW=10,000), 1-MCP/α-cyclodextrincomplex (5 wt. %, 1-MCP content=3.4%), cochineal red (0.5 wt. %), andisopropyl alcohol (49.5 wt. %) were placed in a round bottom flask. Thecontents of the flask were mixed using a magnetic stirrer for 0.5 hoursat room temperature. Isopropanol was then removed at 40° C. underreduced pressure on a rotary evaporator. The resulting mass was formedin the form of a stick and then evenly spread on paper with a weight of100 g/m² and an area of 6.9 cm×7.8 cm. After drying, samples wereprepared for analysis and tested for 1-MCP per 1 cm² of support. Thepaper with the mass applied was cut and placed in a 250 mL bottle, then2 mL distilled water was added to the bottle and sealed with a Mininert®valve plug, followed by 250 μL cis-2-butene with a gas-tight syringe.The samples were shaken for 30 minutes at a frequency of 600 cycles/min.

The concentration of 1-MCP was determined against the standard, whichwas cis-2-butene, using a gas chromatograph equipped with a PoraBOND Qcolumn: 25 m×0.25 mm (i.d.)×3 μm and a flame ionization detector (FID).Cis-2-butene was used as a standard because it has the same responsefrom an FID detector as 1-methylcyclopropene. From a previously preparedtest in a 250 mL bottle, 250 μL gas was withdrawn with a gas-tightsyringe and injected into the above-mentioned column under the followingconditions: temperature of the split/splitless dispenser 120° C.;isothermal 120° C., temperature of the FID 240° C. detector, split 20:1,carrier gas flow (helium) 50 cm/s. After a single application, theconcentration of 1-MCP on the material as mentioned above was 0.0122mg/cm².

Example 2

Coconut oil (53 wt. %), emulsifier SE-PF (20 wt. %), stearic acid (10wt. %), beeswax (9.5 wt. %), cochineal red (0.5 wt. %),polyvinylpyrrolidone (PVP) (2 wt. %, MW=10,000), and a1-MCP/α-cyclodextrin complex (5 wt. %, 3.3% 1-MCP) was mixed using amechanical stirrer in a round bottom flask placed in an oil bath at 70°C. until a uniform consistency was obtained. The mass obtained wasformed in the form of a stick and tested for 1-MCP per 1 cm² of 100 g/m²paper.

After a single application, the concentration of 1-MCP on the materialas mentioned above was 0.0106 mg/cm². The concentration was determinedanalogously to Example B-1.

Example 3

1-Methylcyclopropene/α-cyclodextrin complex (50 wt. %, content of 1-MCP3.3%), beeswax (24 wt. %), candelilla wax (24 wt. %), andpolyvinylpyrrolidone (PVP) (2 wt. %, MW=10,000) were placed in a mortar.The substances were mixed for 15 minutes to obtain a uniformconsistency. The obtained mass was formed in the form of a stick andtested for 1-MCP per 1 cm² of 100 g/m² paper.

After a single application, the concentration of 1-MCP on the materialas mentioned above was 0.007805 mg/cm². The concentration was determinedanalogously to Example B-1.

Example 4

Beeswax (24 wt. %), candelilla wax (24 wt. %), and polyvinylpyrrolidone(PVP) (2 wt %, MW=10,000) were placed in a beaker and heated to melt at50° C., after which 1-MCP complex with α-cyclodextrin (50% by weight,1-MCP content was 3.3%) was added. The ingredients were mixed to ahomogeneous consistency. After cooling, the resulting mass was formedinto a stick and tested for 1-MCP per 1 cm² of 100 g/m² paper.

After a single application, the concentration of 1-MCP on the materialas mentioned above is 0.01026 mg/cm². The concentration was determinedanalogously to Example B-1.

Example 5

1-Methylcyclopropene/α-cyclodextrin complex (30 wt. %, 1-MCP content3.3%), beeswax (20 wt. %), candelilla wax (20 wt. %), andpolyvinylpyrrolidone (PVP) (30 wt. %) were placed in a mortar. Thesubstances were mixed for 15 minutes to obtain a uniform consistency.The resulting mass was formed into a stick and tested for 1-MCP per 1cm² of 100 g/m² paper.

After a single application, the concentration of 1-MCP on the materialas mentioned above was 0.02645 mg/cm². The concentration was determinedanalogously to Example B-1.

Example 6

Beeswax (20 wt. %) and candelilla wax (20 wt. %) were placed in a beakerand heated to melt at 50° C., after which 1-MCP/α-cyclodextrin complex(30 wt. %, 1-MCP content was 3.3%) and polyvinylpyrrolidone (PVP) (30wt. %) were added. The components were mixed to a homogeneousconsistency. After cooling, the resulting mass was formed into a stickand tested for 1-MCP per 1 cm² of 100 g/m² paper.

After a single application, the concentration of 1-MCP on the materialas mentioned above is 0.02186 mg/cm². The concentration was determinedanalogously to Example B-1.

Example 7

1-Methylcyclopropene/α-cyclodextrin complex (35 wt. %, 1-MCP content3.3%), glycerol (30 wt. %), and polyvinylpyrrolidone (PVP) (35 wt. %)were placed in a mortar. The substances were mixed for 15 minutes toobtain a uniform consistency. The resulting mass was formed into a stickand tested for 1-MCP per 1 cm² of 100 g/m² paper.

After a single application, the concentration of 1-MCP on the materialas mentioned above was 0.02894 mg/cm². The concentration was determinedanalogously to Example B-1.

Example 8

Beeswax (7.5 wt. %), candelilla wax (7.5 wt. %), and glycerol (15 wt. %)were placed in a beaker and heated to melt at 50° C., after which1-MCP/α-cyclodextrin complex (30 wt %, 1-MCP content was 3.3%) andpolyvinylpyrrolidone (PVP) (30 wt %) were added. The components weremixed to a homogeneous consistency. After cooling, the resulting masswas formed into a stick and tested for 1-MCP per 1 cm² of 100 g/m²paper.

After a single application, the concentration of 1-MCP on the materialas mentioned above was 0.02845 mg/cm². The concentration was determinedanalogously to Example B-1.

The 1-MCP concentration was also analyzed at 100% humidity at roomtemperature using the sticks prepared in Examples B-3 and B-4. The papersheet with the mass applied was placed in a 900 mL glass vessel. Asponge soaked in water was inserted into the dish and then sealed, and250 μL of cis-2-butene was introduced with a gas-tight syringe.

The concentration was determined against the standard, which wascis-2-butene, using a gas chromatograph equipped with a PoraBOND Qcolumn: 25 m×0.25 mm (i.d.)×3 μm and a flame ionization detector (FID).Cis-2-butene was used because it has the same response from an FIDdetector as 1-methylcyclopropene.

For analysis, 250 μL gas was collected with a gas-tight syringe andinjected into the above-mentioned column under the following conditions:temperature of the split/splitless dispenser 120° C.; isothermal 120°C., temperature of the FID 240° C. detector, split 20:1, carrier gasflow (helium) 50 cm/s.

The analysis was performed on a gas chromatograph, testing theconcentration of [μL/L] of 1-MCP released over time. The results areshown in FIGS. 4 and 5.

C. Packaging

Example 1

Film Production

25% by weight of a 1-methylcyclopropene/α-cyclodextrin complex with 3.3%1-MCP was mixed with 75% by weight of ethylene vinyl acetate copolymer(Evatane® 28-03) and placed in a co-rotating twin screw extruder BTSK20/40D with block heating to 80° C. The composite was extruded through a3 mm diameter nozzle at a speed of 2 kg/h. The extruded composite wascooled with air and then granulated mechanically.

The content of 1-MCP was determined against a cis-2-butene standardusing a gas chromatograph equipped with a flame ionization detector(FID) and a PoraBOND Q column: 25 m×0.25 mm (i.d.)×3 μm. The content of1-MCP in the granulate was 0.42% by weight as calculated by the formulaaccording to the CIPAC/4669/method.

The granulate composite prepared in this way was coextruded with PETgranulate to form a three-layer film in the ABA format where each Alayer is 10% and the B layer 80% of the finished film. The addition of1-MCP containing granules to layer A is 1% by weight.

The co-extrusion process was carried out using a single-screw extruderat 260° C. to obtain a 0.5 mm thick film.

The co-extruded film was analyzed with respect to MCP content using aPoraBOND Q column: 25 m×0.25 mm (i.d.)×3 μm and a gas chromatographcoupled with a triple quadrupole mass spectrometer (Shimadzu,GCMS-TQ8040). The analysis was carried out at 120° C. in product ionscan mode, 120° C. dispenser temperature, 1:1 split, 55 cm/s carrier gasflow.

Analysis of the 1-MCP content in the film was done by crushing a sampleof 100 cm² of film and then placing it in a gas-tight vial with a volumeof 25 mL in 100% humidity, then a standard was added, which was 250 nLcis-2-butene. After two hours of incubation, the analysis was performedby injecting 250 μL of gas withdrawn from the vial. FIG. 40 is anexemplary chromatogram of the released 1-methylcyclopropene. FIGS. 41and 42 are mass spectra of the released 1-MCP and cis-butene referencestandard, respectively. The 1-MCP content calculated against thestandard was 10.1 nL/L from 1 cm² of a 0.5 mm thick film.

A basket was made of the film prepared in this way, and the content of1-MCP was determined after the thermoforming process.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

What is claimed is:
 1. A composition comprising: (a) a complex of1-methylcyclopropene and α-cyclodextrin and (b) a polymer binderselected from the group consisting of polyvinylpyrollidone andcopolymers thereof, polyvinyl alcohol and copolymers thereof, polyvinylacetate copolymers, and combinations thereof, wherein the ratio ofpolymer binder to complex on a weight to weight basis ranges from about0.5:1 to about 3:1, and wherein the composition is capable of releasingthe 1-methylcyclopropene in the form of a gas when exposed to moisture,the composition having a release profile characterized in that whenexposed at room temperature in a sealed vessel to conditions of 85%relative humidity, the composition releases substantially no1-methylcyclopropene after a time period of at least 1 hour afterexposure and thereafter continuously releases 1-methylcyclopropene forat least 5 hours after exposure.
 2. The composition of claim 1 whereinthe ratio of polymer binder to complex on a weight to weight basis isabout 1:1.
 3. The composition of claim 1 wherein the polymer binder hasa molecular weight ranging from about 5,000 to about 15,000.
 4. Thecomposition of claim 1 wherein the polymer binder has a molecular weightof about 10,000.
 5. The composition of claim 1 further comprising ahygroscopic agent.
 6. The composition of claim 5 wherein the hygroscopicagent is selected from the group consisting of glycerol, glucose, andcombinations thereof.
 7. The composition of claim 1 further comprising ahumidity-indicating dye.
 8. The composition of claim 1 wherein thecomposition has a release profile characterized in that when exposed atroom temperature in a sealed vessel to conditions of 85% relativehumidity, the composition releases substantially no 1-methylcyclopropeneafter 2 hours.
 9. The composition of claim 1 wherein the composition hasa release profile characterized in that when exposed at room temperaturein a sealed vessel to conditions of 85% relative humidity, thecomposition releases substantially no 1-methylcyclopropene after 3hours.
 10. The composition of claim 1 wherein the composition has arelease profile characterized in that when exposed at room temperaturein a sealed vessel to conditions of 85% relative humidity, thecomposition releases substantially no 1-methylcyclopropene after a timeperiod of at least 1 hour after exposure and thereafter continuouslyreleases 1-methylcyclopropene for at least 24 hours after exposure. 11.The composition of claim 1 wherein the composition has a release profilecharacterized in that when exposed at room temperature in a sealedvessel to conditions of 85% relative humidity, the composition releasessubstantially no 1-methylcyclopropene after a time period of at least 3hours after exposure and thereafter continuously releases1-methylcyclopropene for at least 24 hours after exposure.
 12. Thecomposition of claim 1 wherein the composition is in the form of a stickthat can be manually applied to a surface of a substrate.
 13. Anadhesive label comprising (a) a substrate having a first surface and asecond surface; (b) the composition of claim 1 provided on the firstsurface; and (c) an adhesive provided on the second surface.
 14. Theadhesive label of claim 13 wherein the substrate comprises a papersubstrate.
 15. The composition of claim 1, wherein the1-methylcyclopropene is present in the composition in an amount of fromabout 0.825 wt % to about 2.2 wt %.
 16. A composition comprising: (a) acomplex of 1-methylcyclopropene and α-cyclodextrin and (b) a polymerbinder selected from the group consisting of polyvinylpyrollidone andcopolymers thereof, polyvinyl alcohol and copolymers thereof, polyvinylacetate copolymers, and combinations thereof, wherein the ratio ofpolymer binder to complex on a weight to weight basis ranges from about0.5:1 to about 4:1, and wherein the composition is capable of releasingthe 1-methylcyclopropene in the form of a gas when exposed to moisture,the composition having a release profile characterized in that whenexposed at room temperature in a sealed vessel to conditions of 85%relative humidity, the composition releases substantially no1-methylcyclopropene after a time period of at least 1 hour afterexposure and thereafter continuously releases 1-methylcyclopropene forat least 5 hours after exposure.
 17. The composition of claim 1, whereinthe 1-methylcyclopropene is present in the composition in an amount offrom about 0.66 wt % to about 2.2 wt %.